FR2500889A1 - VANE PUMP - Google Patents

Abstract

THE INVENTION CONCERNS A VANE PUMP INCLUDING A FRONT CASE 9, A REAR CASE 10, A DRIVE SHAFT 2 AND A ROTOR 5 MOUNTED ON THIS DRIVE SHAFT. THIS PUMP IS CHARACTERIZED IN THAT IT INCLUDES A RING FORMING CAM 8 TAKEN AS A SANDWICH BETWEEN THE FRONT CASE 9 AND THE REAR CASE 10 SO AS TO FORM A WORKING CHAMBER 11 OF THE PUMP, A CERTAIN NUMBER OF PALLETS 7 MOUNTED ON THE ROTOR SO AS TO BE ABLE TO MOVE RADIALLY TOWARDS THE EXTERIOR SLIDING IN CONTACT WITH THE INTERNAL SURFACE OF THE RING FORMING CAM 8, WHEN ROTOR 5 IS DRIVEN IN ROTATION, AND A TURBINE 22 TO APPLY APPROPRIATE PRESSURE TO THE FLUID INTRODUCED INTO THE DIRECTION IN WHICH THE FLUID FLOWS, THIS TURBINE BEING ARRANGED IN THE REAR CASING 10. APPLICATION TO ASSISTED STEERING OF A MOTOR VEHICLE.

Description

The present invention generally relates to a pump for

  pallets used with a power steering of a motor vehicle and more particularly a turbine provided with an inlet conduit for supplying the fluid introduced under pressure in order to prevent the appearance of cavitation, that is to say to reduce noise while limiting the temperature rise of

  oil. In addition to the aforementioned turbine, the present invention is also

  relative to a light and small cam ring

  housed between the front and rear casings.

  When a conventional vane pump is used for a power steering of a motor vehicle, the phenomenon of cavitation easily appears in the fluid introduced into this pump due to the vacuum created on the input side, resulting in the production of a noise accompanied by a rise in temperature of

fluid.

  In addition, with a conventional vane pump, since the cam ring is usually designed to be attached to the front housing or to the rear housing, it is connected to a housing portion for this ring, which is provided either on

  the front casing is on the rear casing, which

  that the vane pump has significant weight and dimensions

  aunts. The present invention aims to solve these problems and its main purpose is to provide a pump to

  pallets which prevents the appearance of the phenomenon of cavitation,

  ie the production of noise without increasing the temperature of the fluid introduced. Another object of the invention is to provide a vane pump in which the cam ring is mounted between the front and rear casings with a relatively

  simple, without increasing the size and weight.

  For this purpose, the vane pump according to the invention is characterized in that it comprises a turbine provided on the inlet side in order to increase the pressure of the fluid introduced into the pump.

  pallets, which makes it possible to prevent the actual appearance of the phenomenon

  leads to cavitation that is to say the production of noise.

  According to a complementary feature of the invention

  25008g9 tion, the vane pump comprises a cam ring sandwiched between the anterior and posterior casings, the assembly being held by means of bolts passing through holes drilled in these elements, without thereby using a portion constituting a housing for the cam ring in the front or rear casing as in the case of conventional vane pumps, in order to

  reduce weight and dimensions.

  An embodiment of the present invention will be described hereinafter by way of non-limiting example with reference to the appended drawing in which: FIG. 1 is a view in axial section of a form

  preferred embodiment of the vane pump according to the invention.

  Figure 2 is a cross-sectional view taken

  along the line II-II of Figure 1, showing the cam ring.

  FIG. 3 is a cross-sectional view taken along line IIIIII of FIG. 1, showing the posterior casing; FIG. 4 is a cross-sectional view taken

  along the line IV-IV of Figure 1, showing the posterior housing.

  Figure 5 is a cross-sectional view taken

  along the line V-V of Figure 1, showing the front casing.

  FIG. 6 is a cross-sectional view taken along the line VIVI of FIG. 1, showing the cross-section of the

front casing.

  Referring to FIGS. 1 to 6, the form will be described

  preferred embodiment of the vane pump according to the invention when

  that this pump is used to operate a power steering

of a motor vehicle.

  In these figures, we see a vane pump according to the invention generally designated by the reference 1 and a drive shaft 2 designed to be rotated by a motor of a vehicle (not shown) by the intermediate of a pulley 3 and a belt 4. A rotor 5 is fixed to the drive shaft 2, so as to rotate with last, and this via appropriate moyexs such as key or splines, this rotor 5 being fixed in a suitable position on the drive shaft. 2 by means of a circlip 6. A plurality of vanes 7 are mounted on the rotor 5 and sonat embcttdOE sliding in respective slots 5a provided

  in radial directions. A cam ring surrounds and forms

  25008a9 me a housing for the rotor 5 on which are mounted the vanes 7. The cam ring 8 comprises two large arcuate surfaces Ci, two small arcuate surfaces C2 and two first cam surfaces C3 and two second cam surfaces C4 included each between two large and small arched surfaces. The vane pump according to the invention comprises

  elsewhere an anterior casing 9 and a rear casing 10 which

  between them hold the cam ring 8 and which constitute a

  working chamber 11 in combination with the cam ring 8.

  The front casing 9 is provided with a first inlet duct 13 communicating with an inlet orifice 12, an outlet duct 15 communicating with the outlet orifice 14, a pair of discharge passages 16 whose one end communicates with the outlet duct

  while the other end of each of these communi-

  only with one of the second cam surfaces C4 of the ring forming

  cam 8, a groove 17 for applying a back pressure to the pallet

  and a plurality of holes 18 for applying a counterpressure

  to the pallets one end of each of which communicates with the groove 17 while the other end communicates with the conduit

output 15.

  Furthermore, the rear casing 10 is provided with a third inlet duct 20 which communicates with the first inlet duct 13 provided in the front casing 9, via a second inlet duct 19 provided in the cam ring 8, and a pair of first load chambers 21 which communicate with the first cam surfaces C3 of the cam ring 8 and which

  are fed from the third inlet conduit 20.

  The vane pump according to the invention further comprises a turbine 22 which is in the third inlet duct

  20. This turbine 22 is attached to one end of the drive shaft.

  2 and it rotates in the same direction as the rotor 5 of the

vane pump.

  The front casing 9 furthermore comprises a pair of second charging chambers 23 which communicate with the first

  charging chambers 21 provided in the posterior casing 10, by means of

  two load passages 24 provided in the forcing ring.

  8. Reference 25 indicates two passages of leakage

  oil one end of each of which communicates with a

250088'9

  space between the anterior casing 9 and the drive shaft 2 while the other end communicates with the pair of second charging chambers 23 provided in the anterior casing 9. The pump according to the invention also comprises a seal of sealing 26, a bearing 27 through which the shaft 1'ement 2 eld is rotatably mounted in the front casing 9, two annular seals 28 housed in grooves provided in the ring forming

  cam 8, in order to seal the contact surfaces between the forcing ring

  mant cam 8 and the casings anterior 9 and posterior 10, a plate

  front 29 intended to close the front surface of the sump

  10, an annular seal 30 housed in a groove provided in the front plate 29 to seal the contact surface between the front plate 29 and the rear housing 10, a pair of positioning pins 31 ensuring the implementation position

  cam ring 8 with respect to the front casings.

  10, a pair of holes 32 receiving the nipples 31

  and provided respectively in the anterior casing 9 and the casing pos-

  10, bolts 33 assuring the assembly of the front housing 9 and the rear housing 10 with the cam ring 8 sandwiched between them, four holes 34 for the passage of the bolts 33, a safety valve 35 arranged in the outlet orifice in order to evacuate to the outside the fluid giving rise to an overpressure, and

  a valve 36 controlling the fluid flow.

  In the vane pump according to the invention which comes

  to be described above, the cam ring 8 is made of

  wich between the anterior casing 9 and the rear casing 10, this

  ring 8 being provided with the second inlet duct 19, one end of which

  mite communicates with the first inlet duct 13 provided in the front casing 9 while the other end. communicates with the

  third inlet duct 20 provided in the rear casing 10.

  The cam ring 8 also includes the two pairs of passengers.

  load management 24, one end of each of which communicates with the pair of first load chambers 21 provided in the housing

  posterior 10 while the other ends of these passages

  communicate with the pair of second charging chambers 23 provided in the front housing 9. Finally, the cam ring 8 is pierced with holes 34 for the passage of the bolts 33, one end of these holes c uniquani with corresponding holes provided in the

  front casing 9 while the other ends of these holes

  communicate with corresponding holes in the sump.

10.

  Therefore, it is not necessary to provide a housing portion for the cam ring either in the front housing or in the rear housing, as is the

  case in a conventional vane pump.

  We will now describe how the

  vane pump constructed according to the invention.

  When the drive shaft 2 and the rotor 5 are

  rotated by the engine of the motor vehicle, by the

  3 of the belt 4 and the pulley 3, the vanes 7 mounted on the rotor 5 are moved outwards under the effect of the centrifugal force and slide on the inner face of the ring forming

  cam 8, being pressed cantre this face. Therefore, the variability

  volume of the spaces delimited by each pair of vanes 7 causes the introduction of the oil, from an unrepresented oil reservoir, through the inlet orifice 12, the first conduit

  13 and the second input duct 19, in the third con-

  20. The oil thus introduced is pressurized in the third cmduit input 20 under the action of the turbine 22 and is then introduced under pressure into the working chamber 11

  of the pump, through the pair of first charging chambers 21.

  The oil introduced into the working chamber 11 of the pump is transmitted to the power steering (not shown) through the discharge passages 16, the outlet duct 15, the outlet orifice 14 and the flow control valve 36. arranged in the hole of

exit 14.

  When the vanes 7 are pushed inside their respective slots 5a, the pressure applied to the lower or inner ends of the vanes 7 is discharged into the outlet duct 15 through the groove 17 and the holes 18 so that the

  pallets 17 can move regularly in this direction.

  The leaking of oil flowing from the working chamber Il of

  the pump towards the drive shaft 12 is returned di-

  directly to the pair of first charging chambers 21, through the pair of passages 25 ensuring the return of the oil leak. This

  used to improve the efficiency of the pump since the energy losses

  are relatively low compared to a previously known vane pump in which the oil leak is returned to

  through the first inlet duct 13.

  In addition, in the vane pump according to the invention, since the pressure is applied to the oil introduced into the vane pump in the direction in which the oil is fed,

  in other words, the fluid introduced is forced into the first chambers

  21, it is indeed possible to prevent the

  the cavitation phenomenon, that is, the production of noise, while keeping the fluid at a relatively low temperature.

  On the other hand, although in the form of execution of the

  As described above, the turbine is provided in the inlet duct of the vane pump without a side plate, in order to reduce rotational friction, to improve the efficiency.

  of the pump and to reduce the number of elements required for

  truction of this pump, it is naturally possible to use

  for the vane pump a turbine provided with such a side plate

  rale. As previously described, in the pump

  According to the invention, the rotor is mounted on the drive shaft.

  a number of pallets are mounted on this rotor,

  a cam ring surrounds the rotor on which the pallets are mounted, and the cam ring is sandwiched between the front and rear casings so as to thereby form a working chamber of the pump. When the rotor is rotated by

  the drive shaft, the paddles mounted on the rotor moves

  outwardly under the action of the centrifugal force while sliding in contact with the inner face of the cam ring, and consequently the volume variation of the spaces delimited by the

  pairs of neighboring pallets causes the introduction of the oil to

  firing the tank into the working chamber of the pump, through the first, second and third inlet ducts, the first load chambers, the load passages and the second load chambers, and additionally the evacuation of this oil outwardly through the working chamber of the pump, the outlet duct and the outlet port. Since the turbine is designed to apply pressure to the chamber of

  pump, in the inlet duct, to force the oil

  under pressure, it is possible to increase the pressure of the oil as a function of the speed of rotation of the turbine, in order to prevent the appearance of the phenomenon of cavitation, to reduce the noise and to limit the raising the temperature of the oil introduced.

  In addition, in the vane pump according to the invention

  tion, since two pairs of load paths are provided for in

  the cam ring, one end of each of these passages

  communicating with the second load chambers provided for in the

  anterior while the other end of each of these passages communicates with the first load chambers provided in the rear housing, and since one end of each of the bolt holes provided in the cam ring communicates with a hole corresponding in the front casing while the other end communicates with a corresponding hole provided in the rear housing, it is possible to sandwich the cam ring between the anterior housing and the rear housing, by means of the bolts inserted into the corresponding holes, without the need to provide a portion constituting a housing for

  the cam ring is in the front housing or in the car-

  laterally, as is the case with conventional vane pumps.

  tional. This has the practical consequence that the vane pump

  according to the invention is light and small dimensions.

REVEIMICATIONS

  Pallet pump comprising an anterior casing (9), a rear casing (10), a drive shaft (2) and a rotor (5) mounted on this shaft, characterized in that it comprises a ring forming a cam (8) sandwiched between the anterior casing (9) and the rear casing (10) so as to form a

  working chamber (11) of the pump, a number of puck-

  (7) mounted on the rotor so that it can move

  radially outwards by sliding in contact with the sur-

  inner face of the cam ring (8), when the rotor (5) is rotated, and a turbine (22) for applying a suitable pressure to the fluid introduced in the direction in which the fluid flows, this turbine being arranged in the

  rear casing (10), being attached to one end of the armature

  drive (2) and rotating in the same direction as the rotor (5), so that it is possible to prevent the appearance of the cavitation phenomenon or the production of noise caused by

  cavitation of the fluid in the vane pump.

  Pallet pump according to Claim 1, characterized in that the front casing (9) comprises an inlet orifice (12), a first inlet duct (13) communicating with the inlet orifice, an orifice outlet (14), an outlet duct (15)

  communicating with the outlet (14), a pair of

  discharges (16), one end of each of which communicates

  than with the outlet duct (15) and a plurality of holes

(34) Bolt passage.

  Pallet pump according to one of claims 1 and 3,

  2, characterized in that the rear casing (10) comprises a third inlet duct (20), a pair of first load chambers (21) extending from the third inlet duct (20) and a second

  a plurality of bolt holes (34).

  Pallet pump according to one of claims 1 to

  3, characterized in that the cam ring (8) comprises a second inlet duct (19) whose one end communicates with the first inlet duct (13) provided in the front casing (9) while the another end communicates with the third inlet duct (20) provided in the rear casing (10), load passage pairs (24), one end of each of which communicates with the pair of first charging chambers (21). ) provided in the rear housing (10) while the other end of each communicates with the pair of second load chambers (23) provided in the front housing (9), and a plurality of holes (34). passing the bolts, whereby the cam ring (8) is sandwiched between the front casing (9) and the rear casing (10), the assembly being effected by means of a plurality of bolts (33). ) inserted in the holes (34), without the need to provide any portio n constituting a housing for the ring forming

  cam in the front casing (9) or posterior (10), a

  appropriate connection being established between the ducts, chambers and passage provided respectively in the two previous casings

(9) and posterior (10).

  Pallet pump according to one of claims 1

  to 4, characterized in that it further comprises a pair of annular seals (28) for sealing the contact surfaces between the front casing (9) and the ring forming

  cam (8) on the one hand and between the rear casing (10) and the

  the cam ring (8) on the other hand, the annular seals

  (28) being housed in respective grooves respectively

  in the casings anterior (9) and posterior (10).

  Pallet pump according to one of Claims 1 to

  , characterized in that it comprises a safety valve (35) for evacuating out any excess pressure, this safety valve being disposed in the outlet (14), and a flow control valve ( 36) to adjust the amount of

  fluid supplied under pressure from the vane pump, this

  the control valve being arranged also in the orifice of

output (14).